Little Mark Tube 800 clipping issue

IronLung1986 · #1 05-30-2010, 01:18 AM

hey everybody, this is my first time starting a new thread. i'm hoping someone might be able to advise me on an issue with my new amp...

i recently bought a new markbass little mark tube 800, basically a solid-state amp with a tube in the preamp. it sounds great and seems to be working perfectly but i have noticed one thing that troubles me: it appears to have an auto-kill feature where it will simply mute itself if it clips too badly. when this happens you need to turn it off and then back on for it to work again. my bass is a warwick corvette $$, which as most of you know has quite a powerful output. if i set everything on the amp to noon, including the master volume and gain, then max the treble on the bass, i can cause it to "auto-kill" by striking the string with force. the instruction manual says nothing about it. i'm wondering if this is a normal feature meant to protect the amp from blowing, or a defect/irritating thing for which i should return it.

Stumbo · #2 05-30-2010, 01:29 AM

You might want to check out this TB link on what seems to be the same topic: MarkBass Little Mark Tube Gain issue

IronLung1986 · #3 05-30-2010, 01:42 AM

yea i saw that thread. the issue is similar but what i'm really wondering is if the "auto-kill" is supposed to happen. it completely disables the amp when it clips badly and even though i would certainly avoid this anyway, i'd like to know if it's normal or not.

JimmyM · #4 05-30-2010, 01:58 AM

no, it's not normal. it should only shut down if it overheats, and even when clipping, it shouldn't overheat. but for the obvious question...you are using a 4 ohm speaker load or greater, right?

IronLung1986 · #5 05-30-2010, 10:32 AM

yes my speaker is a 4 ohm 410.

moggieman · #6 06-13-2010, 08:35 PM

bump for similar situation. anyone have a reason why this happens?

edit: I'm using an LM II with the high and vpf boosted. Master at noon and gain around 9 o'clock. American std. J-bass. Auto-killed when I kicked the mastotron on and picked hard.

BurningSkies · #7 06-13-2010, 08:46 PM

Sounds like you both are overloading the input extremely hard. Make sure you have the input gain set up correctly and see if that corrects the problem.

moggieman · #8 06-13-2010, 08:54 PM

So you're just suggesting to cut back on the amp's gain?

edit: I don't have my amp with me atm, but will cutting back on the preamp gain cut back on a lot of my volume?

BurningSkies · #9 06-13-2010, 08:59 PM

Quote:

Originally Posted by moggieman

So you're just suggesting to cut back on the amp's gain?

edit: I don't have my amp with me atm, but will cutting back on the preamp gain cut back on a lot of my volume?

If you're clipping the input gain, then yes, you should pull it back until its no longer clipping. The LM make it easy to do. If the little blue light comes on, you need to bring your gain down. Once it stops coming on, you're all set. If you need to turn the main up from there, then do it. If you're clipping the input you're not really getting any more volume out of it anyway.

moggieman · #10 06-13-2010, 09:04 PM

No it's more than clipping, the amp shut off when i picked aggressively. That was with the mastotron on with max bass though. It's PERFECT with no fuzz, it only kicks off when it's engaged.

**B-string** · #11 06-13-2010, 09:38 PM

Sounds more like over-current shut down. Sounds like you picked the wrong amp to do what you are looking for?

PhatBasstard · #12 06-14-2010, 12:45 AM

Hmmm,
I'm currently running a LMIII (only 500 watts) with 2 Spectors (a 4 and a 6) with EMG's and Aguilar pre's at 18 volts. I dime my volumes (usually) but the tones are usually flat. The outputs are hot to the point I can only run the LMIII input at 9 o'clock before the blue light starts to blink at the hottest attacks (thumb slapping), but it's not so hot that it bothers any of my effects before the amp. Unless your bass' output is very low, 12 o'clock seems like a high setting.

I play some extremely loud gigs with this amp and it barely gets warm, much less cuts out.

moggieman · #13 06-14-2010, 08:57 AM

Do you ever set the gain with pedals engaged? Like fuzz?

PhatBasstard · #14 06-14-2010, 02:47 PM

Quote:

Originally Posted by moggieman

Do you ever set the gain with pedals engaged? Like fuzz?

Not sure if you're asking me or the OP. I set all my pedals up so there are no big volume differences or spikes. When I kick them in or out I want a smooth transition.

IronLung1986 · #15 06-14-2010, 03:20 PM

well for me it happens even without fuzz. if i max out the treble on my bass and play aggressively it will die. and it doesn't seem to matter where the gain is set. it happens even when the blue light isn't flashing. i strongly suspect that the amp will have to be returned at this point. this issue is either a defect, or a safety mechanism indicating that the amp is simply not powerful enough for me.

PhatBasstard · #16 06-14-2010, 03:47 PM

Quote:

Originally Posted by IronLung1986

well for me it happens even without fuzz. if i max out the treble on my bass and play aggressively it will die. and it doesn't seem to matter where the gain is set. it happens even when the blue light isn't flashing. i strongly suspect that the amp will have to be returned at this point. this issue is either a defect, or a safety mechanism indicating that the amp is simply not powerful enough for me.

Have you tried this scenario with a different cab? The fact you say it happens when you dime your treble boost makes me wonder if the tweeter in your cab isn't sending the amp into some kind of protect mode.

moggieman · #17 06-14-2010, 05:04 PM

Quote:

Originally Posted by PhatBasstard

Not sure if you're asking me or the OP. I set all my pedals up so there are no big volume differences or spikes. When I kick them in or out I want a smooth transition.

Everything is straight now with the fuzz/amp gain. I didn't take the time to adjust the gain to my picking. Did this time and everything seems to be working great!

IronLung1986 · #18 06-14-2010, 05:21 PM

Quote:

Originally Posted by PhatBasstard

Have you tried this scenario with a different cab? The fact you say it happens when you dime your treble boost makes me wonder if the tweeter in your cab isn't sending the amp into some kind of protect mode.

no i haven't. i don't own any other cabs unfortunately. i will of course be taking it back to the store at which point i'll try it with a different cab. not sure if it matters, but i don't even use my tweeter. i keep it off all the time.

PhatBasstard · #19 06-14-2010, 06:18 PM

Quote:

Originally Posted by IronLung1986

no i haven't. i don't own any other cabs unfortunately. i will of course be taking it back to the store at which point i'll try it with a different cab. not sure if it matters, but i don't even use my tweeter. i keep it off all the time.

Maybe if you turned it on you wouldn't have to dime your treble.

**B-string** · #20 06-14-2010, 09:50 PM

Quote:

Originally Posted by PhatBasstard

Maybe if you turned it on you wouldn't have to dime your treble.

Nothing better than flooring the gas pedal with the brakes on?